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8. Appendix: Glossary
ASCII
American Standard Code for Information Interchange. A 7 bit binary code
representing the english alphabet, decimal numbers and common punctuation
marks. "Also includes control characters" such as carriage return or end of text.
An 8 bit superset of the standard ASCII codes is often used today to include
foreign characters and other symbols. These supersets are often called
extended ASCII character sets.
Backlight
A backlit display is illuminated from behind to provide nighttime and improved
daytime readability.
Baud Rate
The (data and signaling) bit transmission rate of an RS232 device.
Binary Number
A number written using binary notation which only uses zeros and ones
Bit
The smallest unit of information a computer can work with. Each bit is either 0
or 1. Binary digit.
Bitmap
A representation, consisting of rows and columns of dots, of a graphics image
in computer memory. The value of each dot (whether it is filled in or not) is
stored in one or more bits of data.
Byte
A grouping of eight binary bits
CCFL
Cold Cathode Fluorescent Lamp. A high brightness backlighting source
consists of a fluorescent tube powered by a high voltage A.C. source.
Configuration
The way a system is set up, or the assortment of components that make up the
system. Configuration can refer to either hardware or software, or the
combination of both.
Contrast
The ratio of luminance between the light state of the display to the dark state of
the display.
Controller
The microcontroller or PC used to control the Matrix Orbital display unit.
DB-9
The designation of a connector used in the RS232 interface: 9 pin connector
Firmware
Software (programs or data) that has been written onto read-only memory
(ROM). Firmware is a combination of software and hardware. ROMs, PROMs
and EPROMs and flash EEPROMs that have data or programs recorded on
them are firmware.
Font
A design for a set of characters. A font is the combination of typeface and other
qualities, such as size, pitch, and spacing.
Font Metric
A definition of where font is to be placed, such as margins and spacing
between characters and lines.
Hexadecimal
Refers to the base-16 number system, which consists of 16 unique symbols:
the numbers 0 to 9 and the letters A to F. For example, the decimal number 15
is represented as F in the hexadecimal numbering system. The hexadecimal
system is useful because it can represent every byte (8 bits) as two
consecutive hexadecimal digits. It is easier for humans to read hexadecimal
numbers than binary numbers.
I²C
Short for Inter-IC, a type of bus designed by Philips Semiconductors in the
early 1980s, which is used to connect integrated circuits (ICs). I²C is a multi-
master bus, which means that multiple chips can be connected to the same
bus and each one can act as a master by initiating a data transfer.
Interface
A means by which two systems interact.
